Yes, thank you for the hint. I see it now. I was able to compute the following explicit formula for the vector field:
(x^2/(z-1) + 1, x*y/(z-1), x)
for any (x,y,z) with x^2+y^2+z^2=1 except (0,0,1).
Is it possible to have a tangent vector field on the unit 2-sphere x^2+y^2+z^2 =1 in
3D which vanishes at exactly one point? By the Poincare-Hopf index theorem
the index of such vector field at the point where it vanishes must be 2. Is that possible? If yes, can one write an explicit formula...